#include <iostream>
#include <string>

class User {
private:
    std::string account;
    std::string password;
    std::string email;

public:
    User(const std::string& acc, const std::string& pwd, const std::string& eml = "")
        : account(acc), password(pwd), email(eml) {}

    void displayInfo() const {
        std::cout << "Account: " << account << std::endl;
        std::cout << "Password: " << password << std::endl;
        if (!email.empty()) {
            std::cout << "Email: " << email << std::endl;
        } else {
            std::cout << "Email: Not provided" << std::endl;
        }
    }
};

int main() {
    User user1("user1_account", "user1_password", "666@123.com");
    User user2("user2_account", "user2_password" );

    std::cout << "User 1 info:" << std::endl;
    user1.displayInfo();

    std::cout << "\nUser 2 info:" << std::endl;
    user2.displayInfo();

    return 0;
}
